Estudo da adsorção do herbicida atrazina com carvões ativados e sulfonados

Abstract

In the quest to meet the needs of the world's population for food resources, the use of agricultural pesticides has grown significantly and, as a result, several environmental problems have arisen. Atrazine (ATZ) is one of the most used herbicides in the world, found in surface and groundwater. Belonging to the class of triazines, it has carcinogenic potential and presents high toxicity, which can be cited as one of its harms to human health, acting as an endocrine disruptor. It is characterized by its wide-ranging application in agriculture, high persistence in different aquatic environments, and ability to produce effects, among those already mentioned above, on the neuroendocrine and reproductive systems. Thus, the purpose of the present work is to develop activated carbons from sugar cane bagasse, where these undergo activation with potassium hydroxide (KOH), phosphoric acid (H3PO4) and zinc chloride (ZnCl2 ) and subsequently sulfonation, so that, after carrying out their appropriate characterizations, they could be used in the adsorption process of the herbicide mentioned above, in synthetic solutions. The capacity of activated carbon to remove atrazine and the adsorption mechanism is influenced by the variation of several factors, however in this work, different types of carbon samples and herbicide solutions were used, as well as analyzed variations in the pH of the solutions. The working conditions were concentrations of 100, 200, 300 and 500 mg.L-1, pH scale variation of 3, 6 and 9.0 and amount of adsorbent 0.2g in each adsorption test. Isotherms with very similar characteristics were obtained, presenting great adsorption potential, removing practically all of the atrazine used in the tests, reaching results of 99% efficiency. These results are satisfactory for obtaining activated carbon from sugarcane bagasse, with efficiency in removing the herbicide, making it a viable alternative for the production of adsorbents, paving the way for new improvement and application studies on this topic.